The frigid waters of the Arctic and the Antarctic may seem like hostile habitats. But a variety of marine life -- from algae to whales -- is found beneath these frozen surfaces. The ice-cold surface water is constantly mixed with warm bottom water, spreading nutrients throughout the ocean. This endless churning motion is also linked to Earth's climate.

Birds rely on feathers to keep their bodies warm. Mammals that live in climates like Antarctica insulate their bodies with:

blubber

thick fur

wool sweaters

Are you right?

Correct!

Warm-blooded mammals have an insulating layer of blubber to stay warm in cold water. Orcas -- the so-called "killer whales" -- have a layer of blubber about 10 centimeters thick to keep their bodies warm in the polar seas.

To keep from freezing in the polar waters, some fishes:

have a thick layer of blubber to keep warm

swim constantly to keep from freezing

produce an "antifreeze" protein in their blood

Are you right?

Correct!

Some Arctic and Antarctic fishes produce an "antifreeze" protein that keeps ice crystals from forming in their blood.

Due to the freezing temperatures, animals in the polar seas are always smaller than their relatives in warmer climates.

Fact

or

Fiction

?

Fiction

Many animals in the polar oceans are much larger than their relatives in warmer climates because oxygen (a factor in animal size) is more abundant in cold saltwater.

Sometimes the Sun never sets at the North Pole.

Fact

or

Fiction

?

Fact

When it's summer in the northern hemisphere, the North Pole remains in daylight for 24 hours. When summer comes to the South Pole six months later, the same thing happens.